Three House GOPers won't endorse Romney

9/20/12 10:48 AM EDT

Three of the 240 current House Republicans have not endorsed Mitt Romney’s presidential bid, according to a survey by The Hill.

The holdouts: Reps. Ron Paul of Texas, Justin Amash of Michigan and Walter Jones of North Carolina.

The common thread between the three is that they’re House outliers who frequently depart from the GOP line. Paul, of course, challenged Romney for the Republican nomination this year and told the New York Times in August that he doesn’t “fully endorse” him.

Amash and Jones were two of only three House Republicans who backed Paul’s presidential bid.

While Amash and Paul reflect libertarian discomfort with Romney, Jones’s reluctance to endorse his party’s nominee is rooted in his criticism of the wars in Iraq and Afghanistan.

At least two House Democrats have declined to endorse President Obama's re-election: North Carolina Reps. Larry Kissell and Mike McIntyre.